Runners who dread slowing down can get faster even as they get older. Dee Nelson, in blue T-shirt at left, competes in a 5K race in Potomac, Md., this
Runners who dread slowing down can get faster even as they get older. Dee Nelson, in blue T-shirt at left, competes in a 5K race in Potomac, Md., this month. (Washington Post/Katherine Frey)